JP2923494B1 - Treatment method for dioxin-containing wastewater - Google Patents

Abstract

A method for effectively and economically decomposing and removing dioxin and other organochlorine compounds in wastewater is provided. According to a first aspect of the present invention, a wastewater containing dioxin and other organic chlorine compound is passed through a reaction tower 1 filled with a manganese dioxide catalyst to remove chlorine from the organic chlorine compound in the wastewater. Let go. In the second invention, ozone is supplied to a reaction tower filled with a manganese dioxide catalyst to decompose and remove the organochlorine compound. The manganese dioxide catalyst is preferably used in the form of powder, granules, or a form supported on an inorganic material such as ceramics or an organic material such as a polymer resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to secondary sewage water,
Landfill leachate, rivers, human waste, from the waste water, such as industrial waste water, it is possible to efficiently remove dioxin
The present invention relates to a method for treating dioxin- containing wastewater.

[0002]

As a means to effectively remove dioxins BACKGROUND OF THE INVENTION wastewater, a method of removing from the dioxin tends to be adsorbed to and sludge solubility in water is small, with SS by sand filtration method or flocculation precipitation method It has been known. Further, an oxidative decomposition treatment method using a combination of ultraviolet light and ozone is also known.

However , in the sand filtration method and the coagulation sedimentation method, some soluble dioxins are not removed but remain in the treated water. Further, the oxidative decomposition treatment method using a combination of ultraviolet light and ozone is excellent in the effect of decomposing and removing dioxin in wastewater, but has a problem that the treatment cost by irradiation with ultraviolet light is increased.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems and provides an organic chlorine compound capable of effectively and economically decomposing and removing dioxin and other organic chlorine compound compounds in wastewater. The purpose of the present invention is to provide a method for treating contained wastewater.

[0005]

Dioxin-containing waste water of the present invention has been made in order to solve the above problems, there is provided a means for solving processing method <br/> the powder waste water containing dioxins, diacid particulate <br/> While passing water through a reaction tower filled with a manganese oxide catalyst ,
By supplying ozone more than 3 times (weight ratio) of COD coexisting in water, only dioxin with high chlorine number in wastewater
In addition, it is characterized in that chlorine is eliminated and decomposed from dioxin having a low chlorine number . Further, it is preferable to use a manganese dioxide catalyst in a shape supported by an inorganic material such as ceramics or an organic material such as a polymer resin.

[0006] In the present invention, the wastewater is treated with high chlorine
3 times the COD coexisting in the waste water when contacted with the manganese dioxide catalyst is effective for the chlorine from the emissions desorbed (heavy
By supplying ratio) or more of ozone, high in the waste water
Not only dioxin with chlorine number but also dioxin with low chlorine number
Can also be reduced. Since manganese dioxide catalyst to decompose the ozone in addition to the dechlorination effect, to produce an effective radical species in oxidation degradation, low chlorine number da
Decomposition and removal of ioxin can be promoted. This processing method can be performed with high efficiency and at low cost as compared with the ultraviolet ozone processing method.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below. FIG. 1 is a view showing a reference method of the present invention, wherein 1 is a reaction tank, and 2 is a catalyst filling tank for a manganese dioxide catalyst.
The catalyst-filled layer 2 is filled with a powdered or granular manganese dioxide catalyst, or a manganese dioxide catalyst supported on an inorganic material such as ceramics or an organic material such as a polymer resin. Wastewater containing dioxin is supplied to the reaction vessel 1 from the drain supply line 3, dioxin by oxidizing power of manganese dioxide catalyst while passing through the catalyst-packed layer 2
Desorbed chlorine from emission is taken out from the treated water line 4. As a result, the dioxin concentration in the wastewater is reduced.

[0008] While the invention reference method can be performed effectively and economically dechlorination, for dioxins salts prime is highly toxic when lowered, there is a possibility that rather increase the toxicity undesirable .

FIG. 2 is a diagram showing an embodiment of the present invention.
1 is a reaction tank and 2 is a catalyst packed bed of a manganese dioxide catalyst. In the second invention, an ozone gas diffusing device 5 is provided below the catalyst packed layer 2, and ozone gas is supplied from an ozone supply line 6. The upper part of the reaction tank 1 is closed,
The exhaust ozone gas is decomposed and removed by the exhaust ozone treatment device 7.
The wastewater containing dioxin is supplied from the wastewater supply line 3 to the reaction tank 1, and comes into contact with the ozone gas from the ozone gas diffuser 5 while passing through the catalyst packed bed 2.

Ozone directly decomposes dioxin in wastewater, and in the presence of a manganese dioxide catalyst, generates radical species having a stronger oxidizing power than ozone, and these radical species decompose and remove dioxin more effectively. The amount of ozone added at this time is based on the coexisting COD,
It is desirable that the weight ratio be at least three times the COD. The treated water from which dioxin has been decomposed and removed in this manner is taken out of the treated water line 4. According to inventions of this, in addition to the dechlorination reaction, da by oxidative decomposition reaction due to radical species
Decomposition of ioxin is promoted, and dioxin can be treated more strongly than in the case of the reference method . Examples of these inventions will be described below.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The catalyst-filled layer 2 of the apparatus shown in FIG. 1 is filled with a honeycomb-shaped ceramic carrier carrying a manganese dioxide catalyst, and the waste is landfilled containing dioxins, a kind of organochlorine compound. The ground leachate was passed through so that the residence time was 30 minutes. Table 1 shows the change in the concentration of each dioxin in the raw water and the treated water according to this reference method . In addition, TEQ means a concentration equivalent to toxicity.

[0012]

[Table 1]

As shown in Table 1, in the reference method,
By passing the wastewater through a packed bed of manganese dioxide catalyst,
Dioxins having 6 to 8 chlorine atoms decrease, and 60 to 70
% Removal was obtained. On the other hand, T4CDD with 4 chlorine atoms
_S is increasing. Thus, it can be seen that the oxidation with manganese dioxide causes a dechlorination reaction and the chlorine number decreases. Also, the TEQ has decreased from 17 to 12.

The catalyst-filled layer 2 of the apparatus shown in FIG. 2 is filled with a honeycomb-shaped ceramic carrier carrying a manganese dioxide catalyst, and while supplying 5.5 times the COD of ozone, dioxins are removed. Leachate containing leachate was passed through. The residence time is 30 minutes. Implementation of this invention
Table 2 shows the change in the concentration of each dioxin in the raw water and the treated water according to the example .

[0015]

[Table 2]

In the reference method shown in Table 1, a dechlorination reaction occurs, and dioxins having a large number of chlorines are reduced in chlorination,
Conversely, dioxins with a low chlorine number increased, while manganese dioxide catalyst and ozone were combined.
In the present invention, as shown in Table 2 , high chlorine number and low chlorine
All the dioxins in the number tended to decrease, confirming that effective removal was performed.

Next, raw water having a total dioxin content of 940 pg / L was treated by the reference method , the present invention, treatment with only ozone, and treatment with ultraviolet light and ozone, and the results are summarized in Table 3. As evident from this data,
In particular, in the present invention, a higher removal rate can be obtained as compared with the ozone treatment method or the ultraviolet ray + ozone treatment method.

[0018]

[Table 3]

[0019]

As described above, according to the present invention, diode of the present invention
According to the treatment method for wastewater containing xin , high chlorine content in wastewater
And all dioxins having a low chlorine number can be effectively and economically decomposed and removed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a reference method .

FIG. 2 is a sectional view showing an embodiment of the present invention.

[Explanation of symbols]

1 reaction tank, 2 catalyst packed bed, 3 drainage supply line, 4
Treated water line, 5 ozone gas diffuser, 6 ozone supply line, 7 waste ozone treatment device

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C02F 1/78 B01J 23/34 C02F 1/58

Claims (2)

(57) [Claims] A wastewater containing dioxin is powdered,
Passing water quality in a reaction tower filled with particulate manganese dioxide catalyst
One more than 3 times (weight ratio) of COD coexisting in wastewater
By supplying zon, high chlorine count in wastewater
A method for treating dioxin- containing wastewater, comprising desorbing and decomposing chlorine from dioxins having a low chlorine number as well as toxins . 2. The method for treating dioxin- containing wastewater according to claim 1, wherein the manganese dioxide catalyst is used in a form supported by an inorganic material such as ceramics or an organic material such as a polymer resin.